"We're here to support Sean and the amazing work he continues to do in Haiti," Sedgwick told PEOPLE at Penn's charity event, which raised nearly $6 million and was held at the Montage Hotel in Beverly Hills. "It's a very grass-roots organization, and that's how we discern what charities to support."

As for Sunday's Hollywood Foreign Press Association event, at which the Bacons will appear together, "I've been very nervous." Sedgwick admitted. "I was less nervous today at rehearsal. I was glad to get the muscle memory going. I just don't want to screw up introducing her. We have a little thing we're doing."

Sosie, according to her father, "seems to be so relaxed, it's tough for us to be nervous."

"I keep waiting for her to freak out and melt down, but she seems okay," said Mom.

"The first thing I said is, you have to learn to walk in heels, because she's a flats girl. It took me years to get to know to do it," admits Sedgwick. "She says she has, but I don't think she's done enough rehearsing with heels myself, but I'm quiet at this point."

Otherwise, says Sedgwick, motherhood is the ultimate joy. Children, she says, "turn into these people that you'd rather hang out with than any other people you know. That's a wonderful thing."